Professional Portfolio
Sangmin Lee
aquariusmin01@naver.com
github.com/aquariusmin
Economics and business student turning data, financial research, and service thinking into practical decisions.
Customer analytics, alternative-data economics, corporate valuation, fintech systems, and service MVP planning—structured from question to evidence, analysis, interpretation, and decision value.
Economics & Markets
Business & Finance
Data & Research
Execution & Communication
Case study summary
Seven evidence-led cases
Case 01
Customer Analytics · Strategy
Telecom Customer Churn Analysis
Question · Which customers are most likely to leave, why are they at risk, and which retention response fits each segment?
Decision value · The analysis turns a binary prediction task into a prioritization framework and proposes retention strategies targeting a 5.0 percentage-point reduction in churn; the target has not been achieved or validated.
Boundary · The 5.0 percentage-point churn reduction is a proposed planning target, not an achieved business result.
Case 02
Economics · Alternative Data
Satellite Night-Light GDP Analysis
Question · Can night-light intensity help explain GDP where official statistics are limited, and do urban population and electricity access change that relationship?
Decision value · Night-light data can provide a complementary signal for early market screening, country-risk research, and economic monitoring where conventional reporting is limited.
Boundary · R-squared = 0.819 describes explanatory fit in the reported simple model; it is not 81.9% prediction accuracy.
Case 03
Financial Research · Strategy
Korean Air Financial Analysis
Question · How should Korean Air be evaluated when post-pandemic recovery, large investment needs, leverage, and uncertain cash-flow assumptions cause valuation methods to diverge?
Decision value · When valuation methods diverge, decision-makers need an assumption audit rather than a mechanical average or an attractive headline number.
Boundary · This is conditional classroom analysis, not investment advice or a verified public target price.
Case 04
Fintech · Service Operations
Quant Trading Fleet
Question · What operating infrastructure is required to move trading rules from standalone scripts into a controllable and observable service?
Decision value · The system makes strategy operations inspectable and supports structured validation before any consideration of real-money use.
Boundary · Paper-trading validation only. No real-money operation, returns, win rate, profitability, or capital-growth claim is made.
Case 05
Applied Analytics · Model Selection
Financial AI Model Study
Question · How do preprocessing, regularization, model complexity, and hyperparameters affect validation and test performance?
Decision value · Use additional complexity only when validation evidence justifies it; a more advanced method is not automatically the stronger business choice.
Case 06
Service Planning · MVP
Phorage Brand and Commerce MVP
Question · How can a personal photography concept be translated into a testable product and service experience before public launch?
Decision value · The project demonstrates service planning, MVP prioritization, physical-digital integration, and the definition of launch hypotheses and metrics.
Boundary · Pre-launch MVP only. No public launch, public traction, large-scale orders, or verified sales metrics are claimed.
Case 07
Research Design · Statistics
Blood Type and Personality Survey Study
Question · Does a familiar social belief about blood type and personality remain supported when translated into hypotheses and tested with survey data?
Decision value · The study demonstrates how to turn a popular claim into testable hypotheses and restrict the conclusion to what the evidence supports.
Boundary · One isolated significant result does not prove a broad relationship between blood type and personality.